5_EvolMech1 - Evolutionary Mechanisms I 22.1-22.2...

Info icon This preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
Evolutionary Mechanisms I 22.1-22.2
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 Populations evolve, individuals do not Simpson video
Image of page 2
3 The Modern Synthesis Established in the 1930s and 1940s Connected the units of evolution (genes) with the mechanism of evolution (selection on populations) Integrated Darwinian evolution with Mendelian genetics +
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
4 Architects of the modern synthesis JBS Haldane G Ledyard Stebbins Theodosius Dobzhansky Sewall Wright
Image of page 4
5 Hardy Weinberg principle Given a series of assumptions, allele frequencies and genotype frequencies will not change between generations The assumptions are: No selection No mutation No migration Infinitely large population Random mating
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
6 AA Aa aa AA Aa aa aa Generation 1, “Gene pool” Generation 2, allele freq p and q allele freq p and q AA Aa aa AA Aa aa aa A a a A A a a A a If these assumptions are met, allele and genotype frequencies will not change between generations
Image of page 6
7 Some terminology Imagine a populations made up of 100 diploid individuals: 40AA, 40Aa and 20aa The genotype frequencies are?………. The allele frequencies are?……. The genotype numbers are?……. The allele numbers are…..
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
8 Remember the multiplication and addition rules? If you just roll one die, what’s the chance of getting a 4? What’s the chance of getting 4 twice in a row? The combined probability of independent events occurring together is the product of their individual probabilities
Image of page 8
9 If you just roll one die, what’s the probability of getting either a 4 or a 6? The combined probability of 2 mutually exclusive events is the sum of their individual probabilities
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
10 A A a a 0.5 0.5 Eggs Sperm Under Hardy-Weinberg equilibrium, allele frequencies predict genotype frequencies Here’s a numerical example using Punnett squares: 0.5 0.5 0.25 AA 0.50 Aa 0.25 aa Freq A = p = 0.5 Freq a = q = 0.5 .25 AA .25 aA .25 Aa .25 aa
Image of page 10
11 A A a a p q Eggs Sperm Here’s the same thing using symbols... p q p 2 AA 2pq Aa q 2 aa Always check your work: p + q = 1 p 2 + 2pq + q 2 = 1 p 2 AA pq aA pq Aa q 2 aa
Image of page 11

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
12 The same principle applies when there are more than 2 alleles (although we’ll need to use more than p and q) Alleles: A 1 A 2 A 3 A 4 A 5 A 6 ...
Image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern